Gravity operated timing device



1954 E. BREDIMUS ET AL 2,659,087

GRAVITY OPERATED TIMING DEVICE Filed Jan. 19, 1949 3 Sheets-Sheet 1 Summers E ls/e Bred/mus Warrn Dun/7am Fosfer (mommy 1954 E. BREDIMUS ET AL GRAVITY OPERATED TIMING DEVICE 3 Sheets-Sheet Filed Jan. 19 1949 Warren Dun/7am Foster WWI. fink Gtforncg Feb. 16, 1954 E. BREDI MUS ET AL 2,669,087 GRAVITY OPERATED TIMING DEVICE Filed Jan. 19, 1949 3 Sheets-Sheet I5 E/s/e Bred/mus Warren Dun/70m Fos/er Gttorneg lmaentors Patented Feb. 16, 1954 emes, E

ilsti's'i Flag; said Foster: assignofi 0 mm aha-Pastel, a K515811111 Application 19, 1m;.s'erm Hedi-F02" A primary purpose of myen tionds'to controltheappli'cation of, the; fbrce' ofgravityby the application of the frequency of vibration mhe'rent in a spring to. form, what is in effect a sp'ri'ng motor with a; Walking escapementi-Vembodied therein. Such a device may consistessen'tiallyof a spring, leaf or heiical with. onevend files to vibrateand the other "end 'formedT into, an escape.- ment which when placed' aboutv a elongate'd support, which disposed. ink a more or less. upright position descendssat a ratfetof speedwhich. carefully ,preecontrolledt as desiifiedl according tov the: methods! and; instrunientalitieswhich are describedlandiclaimed herein. For? convenience,,.the end-3. nearer a support andlembodying or carrying an esc'apement is called; nearf or. innerl and the-opposite and freeend far or outer.. The speedtof" descent is deeterminedh by, the...effect'- of; gravity load] andthe vibrational? characteristics:- of the,- spring played, 3.111 as conditibnedbm and in'turn -condi tioning. the escapement bye which the motoris attached! to, its. support.

In its -essence,therefore, outinvention be considered: asincludingtoncom-prismg zit-cantilever springand anescapementnachbeingrconditioned by the other and the escapementseryihg-toattach the. to. its support.- The supportis sufliciently upright So-thattheforceyof' g'ravity eonditioned-by the charaeteristicstoff the spsingeandi its load and controlledby the escapement isuti.- lized to bring the motor and its load downwandlx with predetermined timing. The :inotin'ation of the support from,the'perpendiculan'islones factor in our control iofpthesrate oi descent. The

itself :may be of. arfiat on leaf iorm with-one ora farrendvfifee and the other ornear-end-iormediinto or carrying. anescapementandsattaehing struo+- turehoiz it mayr beta springawire preferablyeirow larr inicross -seetion andwound in thet-form ot a 1 post" or other seams. (elite--19 ment.

tion" of? the'shr'ing and the 1 vibration of the spring and its appliati'on' to the escapement condition tl'i'ia'btion of the'eseapement: The result is a couple of reciprocating forces; each acting o'rith'e' other? and: the net total determining the timing: Atitfiis point. it will'be lisefulfbfiefiy torevi 1 the?" olj'erfiti'on of. Certain of the'ph sicarraetb ofwmchwe'makeuse: The method: and means by. which. we fiflly utilize these, faotbrs Will be clear from the following porti'onbf this spee'ificetijon; the present outline j being preliminary; It, will'beassume'di that by hand, reversal. of a" sup: port, or the; use. of nowi' one of ourmctors; for ooiiveniefibe' described as of the leaf. type}, is placedsin. position at the top off'a support with the.- far' end"0f( the spii ii'giin'clinedupwardlii'fibm ahorizontal plane; This? sfiiih'g should carry a; load} 50th; for util' 5' a'rid' many" cas''sI' foroptimumoperation, especially when a timer oi" the like i's-th'e object to whiclfw' appm'oiirm vention, Thefb'rce of'grayity' wm th'enpausetfie tar end'ofthe springito falliuntilit is checked-by 9.1 lower. p'ointof the escapementl Thi 'sfarr'est of, Inovem'entmust be a't'a p'o'int'b'efore' the inherent travel ofrthe. spring due tothe' f orc'e, of gravity been"comp1eted.' When this check is appii'eii at thenean endthefree end of the spring therefore willicontin'u'eto move downwardly th'us' storingv power in the spring. which imrnediatelyl is "utilized tomove th'efree. or outer end ofi the spring upwardly until this movement in -turn is" arrestedby; an xnpper element of the escapernentI Itis es'sentiaithat' thepower thus 'storedfin-th'e spring inrelation tothecharacteristios of the springan'tt the weight which is applied 'andlthe position of this; .upperpoint of the escapement be sufiicient so that this upwardmovement Wilicontinue until is isarrested-folloWing contact or the; near end of thespr-ingsand by the. upperpoint of the escape The-amplitude off the vibration of the spring-a-tand-hence the pointat which it; is to be arrested is-eongi-itioned by the distance-of the con-- tact pointsofethe escapement from the support andTfIQm-eacH-Qther. V I

Intermediate-the; beginning and the end of both thedownwatdand upper phases of the complete cycle-there-isamoment at which the-entire devices is free: from=theclampingaction of the eseapement, andeis-d-rawn bodily devswnwardiy by theiorce of gravity.-- This bodilydeseentmustbe clearly-differentiated from the upward and-den m ward movements-of the spring-itself, controlled ban-its frequencyeand other characteristics and its leactiand -thezconstruction of the-es'capement;- It mll of coursefi be understood tnamhe arrest= of the spring in its upward and downward travel tion, consideration of the drawings and the subis checked respectively by the clamping action of joined claims. It will be readily understood that the upward and downward points of engagement for purposes of illustration only we are showing of the escapement on the near side of the supcertain preferred embodiments of our invention port in cooperation with the one or two points but changes may be made therein without deof contact of the escapement upon the opposite parting from the spirit of our invention or the side of this support. Certain definite steps or scope of our broader claims.

constructions are necessary to secure satisfactory In the drawings: clamping action at the end of each phase of each Figure .1 is an-elevational side view of a timing cycle and also and more important to afford device utilizing one embodiment of our invention, closely pre-controlled and regular oscillation.-

called for convenient identification the J form, All of the above factors are later presented more by which we illustrate our invention when utifully and with necessary formulae anddirections. lizing a "leafspring.

The same principles, including the recurrent 1 Figure.2 isa fragmentary side view largely in cycles each of two phases, apply to the operation "sect'io'n"" corresponding to Figure 1. of a spring motor of the helical type, although,; Figure 3 is a-fragmentary side elevation which they are not so obvious. Certain added factors corresponds to Figure 1 and shows a variant later discussed arise from the travelling waves '-"-thereof.-

or oscillations of the helix along its longitudinal Figure 4 is a side elevation which shows a axis. The arrest of the helix at the end of the weight which may be employed with the strucdownward phase at a point prior to theexpenditures of Figures 1, 3 and 4 hereof.

ture of the complete efiect of the force of gravity Figure 5"is atop plan view of the structure of sets up a response in the spring which raises it Figure 1 partially in section. through the neutral point and to that at which 1 Figure 6 is an elevational view of an important its upward phase is arrested by an upward esmodificationof our invention wherein the escapement point. provided of course that the prin-' capement isknown for convenience as of the ciples stated above and elaborated hereinafter ftrident form.

are carefully followed. It should be noted that Figure 7 is a fragmentary showing in side elea helical spring made of round wire'is six times vation of a modification of the structure of as eflicient in the amount of energy which it will Figure 6, the tines of the trident being placed store per cubic inch or pound of metal in the further from the fulcrumof the vibrating canti spring in relation to a'fiat. spring of uniform lever and being furtherspa'ced at their point cross section with'a concentrated load. (lvlorof contact with the support thusdecreasing each timer F. Sayre, Kents Mechanical Engineers period of arrested movement of the escapement Handbook, 10-21, Eleventh Edition.) and hence increasing the speed of travel.

This invention also includes the provision of- Figure 8 is a top plan view corresponding to methods of adjustment and instrumentalities Figure 7. whereby when desired a motor and its load may Figure 9 is a top plan view of a variation of be caused bodily to move about the rod in a helical the structure of Figures 6, 7 and 8, showing how descending path of its own. Such movement is to we may secure rotation about a support by imalso closely pre-set and conditioned. To accom f balance caused by offsetting a weight.

plish this result we utilize a predetermined im- Figures -1-0- and 11 are elevational views illusbalance of a vibrating instrumentality as for; trating an escapement, known for convenience example by a couple of forces produced by free-i as of the L type, which'represent modifications dom of vibration along one side of a helical ofthe J and trident-formspreviously mentioned. spring and damping along the other, or by an Figure 1-1 is a modification of Figure 10 wherein unbalanced load. I the cross bar of the L is elongated thus increasing Although our invention can be applied as a the rateof descent.

timer or as motive power for toys and is so illus-. Figure 12 is an illustration in modified isomettrated herein it is not so restricted. Our invenric of our invention as practiced with a helical tion can be used in any device in which it is despring, the load being attached to a motor adsired to utilize the force of gravity as pre-conjacent the support, escapement being of the three trolled by an escapement-operated spring. In point type. i I

short our invention can be applied where ever it Figures 13, 14. and 15 are diagrammatic showis desired to cause gravitational force intermitings, in the form of side elevations very much tently and in a series of pre-set, short and regua exaggerated, illustrating the operation of our lar oscillations to move an object downwardly escapement, the form used in this example being along a generally upright support. of the trident type Figure 13 shows the escape- The objects and characteristics of our invention ment inits upper or ascending limiting position, therefore include the provision of new and im- Figure 14 in its neutral or free or descending proved means and methods whereby the force position, and Figure 15 in its lower or descending of gravity may be utilized in a pre-controlled limiting position. and uniform manner to determine the descent Figure 16 (Sheet 2) is an isometric view of a of an object along a predominantly upright post toy-Woodpecker which is one means by which or other support in a series of pre-timed regular we illustrate our invention when utilizing a heliintermittent movements and if desired its 'ro-tacal 'spring.-'

tion thereabout, and to utilize such methods and Figure 17 is a fragmentary isometric view cormeans as the motivating force for toys, timers, responding to Figure 1 partly broken away but and other devices. Other objects are to condi-' taken from an opposite point of view.

tion predeterminedly the operation of a gravita- Figure 18 is a top plan view of our escapement tional escapement by a spring which is attached t and motor in which a helical spring is employed. to a support thereby and predeterminedly to con-- Figure 19 is a side elevational view corresponddition the operation of the escapement in turn ing to Figure 18.

by the characteristics and control of said spring. Figure 20 is a vertical section taken on the line Still other objects and characteristics will be 26-40 of Figure 21 and looking in the direction apparent from .the remainder of thisspecific'ae of the arrows. a

nsure .11;. :2. i e elevat onal-r ew 518 par: ticular fastening; for attachinga. motor and its load to a platform Figure 22- is. a front. elevational; View. of. the body of this, motor with its. support removed.

Figure 23; corresponds,- to Figure 18. but is a variant illustrating; change. in. direction. ofrotation following a, change in relative; position, of thedamped. and undamped portions of ahelical spring.

Figure 24, corresponding to- Figures 18- and. 23; shows in part howwe; pro-set the bodily rotation of ga motor or"- our; helical. type.

Figures. and 26 are, fragmentary top. plan viewsshowinghow. differences in anglebetween th capcmentloops and thcrfirst coilof a. helix cause difference in rapidity oi bodily rotation,

Figure: 27 is a view largely in. tQDPlan and par-1 tially in section showing: an important variant wherein we. providea partial substitute, for. the damping arrangements as shown in; Figures; 18', 19,.23and24.

As already indicated; this inventiom may be embodied in a. motor making use of either'a leaf or a helical spring. We shall first describe and illustrate our invention as utilizing a leaf, spring. Before stating the characteristics of leaf. springs which accomplish. our purposes,. the principles underlying the construction of our escapernent and the methods by. whichthe load is. determined we; shall, describe, certain embodiments of, our invention.

Figures 1. to dillustrate our invention. as applied to .a timensuch ascan berused for photo graphic and many other purposes, with a spring motorinthe formof a leaf. spring and so formed at itsnear end as to embody both an attachment bywhich it can be mounted upon its support and also, an escapement. Such atimer can bereadi- 1y electrically. or mechanically connected to any object which it. is desiredto control, but. such connections form no part of the. present inventionand hence are not presented. hereby. Also, for-another example of its use, it canbe applied as. atiming agitator, atest tube, for example, being mounted on or adjacent the freeend. of a cantilever spring.

For illustrating, our invention as, it. is. applied to; a. timer itiis desirable to introduce another controlled variant in the form of a pre-set dlfe ference-oi inclination of a support. Therefore base I, which preferably is madev rather heavy both-.for solidity and to discourage sympathetic vibrationsin responseto thoseof atiming'spring,

includes.two-upstanding parallel plates 8.between whicha disct is rotatably. supported upon set screw. 3. Preferably the base and upstanding supports are made of one piece as. by casting. Support or post II is fastened to discv 9, in, any appropriate fashion or may be made integral therewith. Calibrations 12. indicating eithertthe degree of inclination of the support or. the factor which must. be applied. to the wanted determine..- tions because of. this inclination. are placedupon aside of one of the plates. After the-set. screw is loosened the support [2" may. be rotated toany desired angle as indicated between calibrations 1.2 and arrow l3on theside .oithe. support. Thus, a. user mayreadily determinethe angleat which the support is set or at once noteitaeffectupon actimingoperation and fasten the post by tightening l the thumb screw I 0., Inclination of. course decreases. speed of. descent of the motor. and its load-by introducing increased-,;sliding friction atthe .1 fr i tervaliofythe; scan mcnt'. ycl

A. leaf, spring; generally indicated, I5; is. at:- tached to this post by-an escapementgof, the type which for convenience; herein is. designated as the :1 form. For convenience hereinwe occasionally use capital letters as descriptive: of certain constructions, with. their orientation as the let.- ters; appear in print. Thus an upright leg of 9.;J; is; the portion which in aletter J- in type ls upright although in a: drawing. or-in fact it. may be. disposed on: its side. The main body: or upright leg [5- of' the leaf spring is bent'backwardly upon itself into a descending portion [-1- and portion. l8 which is again turned upon itself to. complete'the-J-formt Openings. I9 and 2-9 are formed respectively in thelong leg-or main por tion, of; the J- and the upright or short leg 18, generally parallel. thereto, respectively, through which the post passes. The clearancebetween the-- edges of; these openings and the post: in. relatively small; a matter of a; very fewthousandths or an inch depending upon the particular use. to which adeviceis tobe put. In the illustrations herein for clarity these clearances are exaggerated. The escapement of: this. form has: four points created by theopposite sides of the two openings I9 and Iii. In order to condition the vibration-of the spring and consequentlytheoperation of the escapement we preferably. apply; a weight within certain specified limits',.all 111,8. manner later explained. A. weight 22 may" be moved along the surface of themain-por-tioir It of the spring and by screw 23.- bev set according to calibrations 2t. InFigure 4 we show another similar weight 25 having a, body 26 and: a set screw 21, of less weightthan the device shown in Figure 2. Consequently we may vary the frequency of operation of the-spring motor not only by moving the weights along the-surfaceof the spring but by substitutingweights of different magnitudes. Thus by comparatively few. weights each separately or in combination disposed as desired along the'main arm'ofthe spring we are able to secure; as; many difierent. frequencies as are required for. all ordinary. purposes.

In order-to limit the travel of the spring;motor along the support H a top-stop, preferably re.- movable, is supplied and a. bottom adjustable stop 3:! which may be placed along calibrations 32 at any desired point andheld there by a. screw-33 Also, an upper stop of the type shown as the lower stop and movable along the post may be substituted, thus further increasing the combinations which may be secured.

Onegreat advantagecf the J form of our-in: vention isexemplified by Figure 3. A spring of this type may readily be constructed so that the critical factors are easily changed in advance. In Figure 3 we show a spring motor generally in? dicated as t lliaving anescapement support generally indicated as 35; A main upright arm 360i the J-carries'a weight 32 having a set-screw 38 andcalibrations not shown suchaspreviously described andv as illustrated in Figure 5. The forward end of this spring is turned downward into a cross arm 33 and then backwardly upon itself into a short upright arnidii; these arms being horizontally disposed and generally. parallel: Openings and 42 in-the long and short arms respectively embrace a support 43 which in. this case is shown ascircular in cross secticn hutotherwise may'be'constructed' and mounted as is pest H. By comparison with Figure 2'it will be'seen that cross armtfi is much longer than cross arm It! previously; described and that the angle in short upward arm to is much less than that in arm 20 of the previous construction.

The lengthening of the short arm 39, as for example compared with short arm ll of Figure 1, decreases the amplitude of each vibration and also the time during which the lower portion of the escapement in each phase of each cycle is in clamping contact with the post. Since the frequency of vibration is not changed the net result is a relative increase in the positioning of the escapement in its central or neutral position, with consequently a more rapid bodily descent. Changing the angle of the short upward leg of the J in relation to the cross bar in effect increases the diameter of the opening 42. As will later be explained in more detail, the widening of this opening increases the amplitude of vibration of the spring. To a light extent this increase also postpones clamping action in each phase of each cycle and thus further increases the speed of descent. We have found this second factor of relatively less importance than the others which are set out herein.

In the forms of our invention in which we make use of a leaf spring and to a less extent in those in which we employ a helical spring we have found it possible to use a battery of motors slmultaneously. We have placed a plurality of e."- capement-supports in different positions relative to the circumference of a round support or upon different sides of a square support and arrange for them to support a common load. Thus we are able to increase carrying capacity. For the majority of purposes, however, a single motor as herein described is sufficient.

Our motor, of whatever type, may be raised to starting position by hand or, as in the case of the form about to be described, merely by inversion of its support. Alternatively and for certain applications such inversion or raising may be by power.

Figures 6, 7 and 8 show various forms of a highly important trident form of our invention, wherein the escapement is in the form of a U (in Figure 6 more nearly resembling the Greek capital upsilon) each of the ends of the upright arms of which engage on side of the support while the escapement clamp on the other side is formed by the leftward wall, as viewed in the drawings, of an opening of the main spring which 1 intersects the center of the U parallel to its up right legs. and embraces a supporting post. This construction is particularly simple, inexpensive and versatile. One great advantage of this form is that the entire structure readily can be turned from one end to the other. Therefore it is not necessary to move the motor by hand or otherwise from the bottom of the support to the top for successive operations.

As is fully shown in Figure 6 a support or post shown as square in cross section has a top stop 52, which may be made removable, or movable along the post, or both, and a base 53. Preferably the post is calibrated as shown at 5A. A spring motor generally indicated as 55 includes an escapement generally indicated as 56. A single leaf spring 51 has an opening 58 which embraces post 5|. Aweight 59 controlled by a set screw 60 may be moved along the surface of spring 51 according to calibrations which are not shown but may be similar to those of Figures 5, 8 and 9. The escapement consists of a U-shaped structure consisting of bent sheet metal strips (ii and $2 representing the upright legs of the U fastened as by a rivet 65 or spot welding to spring 51 at the outer or leftward side of opening 58. The inner or rightward side does not engage the post as a part of the escapement cycle.

Figures '7 and 8 show a variation of the structure of Figure 6. They illustrate how a still further increase of th versatility of the structure of Figure 6 can be secured at a very low cost. Post 63, shown as circular, may be mounted as illustrated in Figure 6. A leaf spring 59 is formed with an opening i0, corresponding to 58 previously described, embracing the post. A weight H with a set screw l2 is movable along the surface of the spring in accordance with calibrations 73. The remainder of the escapement mechanismnamely the components of the U portion of the escapement trident-may be formed of two L-shaped pieces of spring metal i l and 15 with the short or cross arms offset and extended along the surface of spring 69 to givespace for the ap plication of a rivet 16 or spot welding. The operation of this form-of our devic is the same as that shown in Figure 6 with the important exception that the legs 14 and i5 of the U are considerably longer and also further spaced from each other. Thus while frequency of engagement with the post is not changed the duration of that engagement and consequently the clamping action are less and the motor descends more rapidly. Provided the points of contact of the near side (right as viewed) of the escapement are equally spaced from a support, amplitude of vibration of our cantilever spring is decreased by an increase of the vertical distance of these near points of contact from the horizontal plane intersecting the far or leftward point.

As a practical manufacturing operation we profer to furnish a plurality of spring motors of this kind each with a U portion of the trident with legs of different lengths rather than to make the U portion removable or adjustable. Costs are thus lessened in this manner and certainty of results increased. With a plurality of springmotors and a plurality of weights, each costing very little indeed, one device of the type of Figures 6, 7 and 8 can readily meet any reasonably desired condition.

As stated more at length in connection with the later discussion of spring motors of the helical form it is often desirable to cause the spring motor to rotate bodily about its support, again in accordance with conditions which are carefully pre-set. As previously stated any condition of imbalance in the motor will accomplish this result. The most simple procedure when a leaf spring is used is to off-set the weight from the longitudinal axis of the spring motor. As shown in top plan in Figure 9 a leaf spring 19 having an opening embraces a support 8! which is circular in cross section. The escapement is composed of the left side of this opening as viewed in this figure and the points of a horizontally disposed U-shaped component added to the central line of the trident with its base or cross bar bisected thereby in the form of arms 82 attached as by a rivet 83 or spot welding. A weight 84 attached by a set screw 85 and set upon one side of the center of the spring and movable in accordance with calibrations 86 causes this structure to rotate anti-clockwise in the direction of the arrow as indicated.

Figures 10 and 11 show the form of our invention applied to a leaf spring which for purposes of convenience herein is called the L. form. A leaf spring 88 having an opening 89 embraces post 90. A downwardly extending leg 9| repre- '9 senting the cross bar of the L terminates in an oil-set point 92 engageable with the support. The sides of the opening 89 and this point compose the elements of the escapenient. A weight 94 controlled by a set screw 95 can be moved along the calibrated surface of spring 83.

The elements of our invention shown in Figure 11 resemble those of Figure 18 except that the cross bar of the L is further extended thus increasing the relative speed of bodily descent, as previously explained in connection with the comparison of the form of Figures 7 and -8 with that of Figure 6 and that of Figure 3 with that of Figure 1. Care must be talren not to this bar sufiiciently long and of such characteristics as to set up independent vibration. In View of the similarity of the structure of Figures 10 and 11, except as to the relative length of bars 9! and 91', the description Figure 1-0 is not being repeated as applied to Figure 11. The reference characters of Figure 10 are therefore applied to Figure -l1 with a prime character added. In: crease of this length lessens amplitude of vibration.

In selecting a proper leaf spring to carry out any of the several forms of our invention hereinabove described, certain criticalfactors should be applied although they may be determined within a relatively wide latitude.

In determining the characteristics of a leaf spring, it is first necessary to find the stiffness in pounds per inch of deflection, a factor known as k. The formula given .in Art and Science of Spring Making (fourth edition, by Barnes, Gibson and Raymond) is asfol'lows:

. m an wherein F=deilection in inches.

L 'length of lever arm in inches or 3.375".

P=load in pounds, assuming unit as I.

=modulus of elasticity "30,000,000 for steel.

[=55 b the moment of inertia,

"The specific values are in accordance with one illustration of our invention ,as .built in accordance with Figure 6. Substituting:

1*rcquency=3.l2 7:7 (W +C' W cycles persec. where Ic=stiifness of spring in pounds per inch of deflection. Wa=weight of spring itself. Wr=weight of load -=carried by spring. 0i=constant 4A for cantilever springs :of *uniform JGIOSS section.

1-0 Substituting known factors for a spring used in the above illustration:

=3.l2 3.58=ll.16 cycles per second A weight of lead of .02 2 1b. is used.

From the above formulae, certain general principles may be readily understood. With an increas of the weight of the load (WL), the rate of vibration is correspondingly decreased. Conversely, a decrease of a rate of vibration makes possible carrying of a load of greater weight under the same conditions. Likewise, with an increase in stifi'ness (k), the rate of vibration is increased, or by decreased stiffness the rate of vibration is decreased. in increase of the crosssection area of a spring I, the moment of inertia, increases the stifiness which is expressed in deflection in pounds per inch. Likewise decreasing the cross-section area of the spring decreases the stiffness. Also, increase in the length of lever arm (L) increases deflection and decrease of the length decreases deflection. By keeping the above formulae and principles in mind, as well as those previously outlined and later discussed more fully as to our method and means applied to an escapement, it is possible to meet any reasonable set of conditions.

As previously stated, we may practice our invention by providing a motor which is powered by a helical instead of a leaf spring, as first and generally illustrated in Figure 12. Since the operation of the escapement in either form of the invention is thesame whether a leaf or a helical spring is employed we are briefly describing this one embodiment utilizing a helical spring at this time and before we discuss in detail the operation of the three point escapement as shown by schematic Figures 13, 14 and 15. Thereafter we shall describe fully the construction and operation of the forms of our invention utilizing a helical spring and illustrate its use.

As is shown schematically in Figure 12 a motor is operated by helical. sprin having free coils at and clamped coils 3?, The operation, purpose, significance and modifications with. damped and undamped coils will be fully dis-cussed later. The motor is attached by an escapement hock 98 to a supported shown as round. An L-shaped platform having a horizontal supporting portion I00 representing the normally upright leg of the L and. an attaching right angled portion i0! representing the cross bar is attached to the helical spring by means generally indicated as l 02 which will be described at length later in connection with Figures 1.8 to 21 inclusive and 27. A load conventionally shown as I.- appears upon the platform. This load may be a carefully determined weight which in accordance with calibrations such as those previously described may be set at .difierent points along the platform or it may be the body of toy as illustrated in Figure 1-6 and described in connection therewith or any other load which may be desired either for purposes of utility or in order to control the frequency and amplitude of vibration of the spring or the speed of bodily descent of the entire device. It will be particularly noted that the escapement hook 188 extends from free coil iii i about the post with a point of contact at the QiQf coil 4 M and .a point of contact Hi6 atthe bottom of the coil, both on the near or right side of the post, and a third and final point of contact it! on the leftward side of the support. Figure 17 upon. Sheet 2 shows substantially-the same escapement construction from the opposite point of view. In this latter instance the three point suspension or contact is as indicated at points M8, M9 and IE9.

We shall now discuss the method of operation of our escapement, with particular'referenc to diagrams of Figures 13, 14 and 15 which are very greatly exaggerated for purposes of clarity. While we have elected to illustrate the operation of the escapement by a three point contact of the trident form of our invention it will be understood that the principles are the same whether exemplified in this form or in the J, L, helical or other forms. In these diagrams support or post P corresponds to supports H, 13, 5|, 68, 8|, 9%, 98, Hi and iii. The escapement is shown diagrammatically as being attached to or embodied in a leaf spring 508 (corresponding to all of the several springs fiat or helical herein illustrated and described) and a U-shaped escapement component diagrammatically indicated as IE9 and having an opening H!) which embraces post P.

The escapement contact or suspension points in this form of our invention include the ends A and B of each leg of U 99 and the edge C of the opening i It of spring we. Side D is-shown as so far removed from the post as to exert no escapement eifect. If desired it may also be positioned so as to be utilized to supplement the clampin action of either point A or B but such an arrangement is not necessary. The down- Ward phase of the first cycle is powered both by inertia due to gravity and preferably bythe resilience of the spring, but the resilience of the spring alone brings the motor back to the position of Figure 13.

It is assumed then that regular cyclic operation begins with the mechanism returned by resilience to the position of Figure 13. Thereupon the force of gravity augmented by the inertia 1 of the load L and the energy stored by the upward phase after the moment of arrest carries the motor through the neutral position of Figure 14 to that of Figure 15. At this moment points B and C engage post P and form a clamp which arrests the downward movement of that portion of the motor which is adjacent the support. As previously stated in outline this check in this downward motion must come at a time when inertia will carry the free end of the sprin still further downwardly thereby storing power therein. This power thereupon is operative to bring spring I68 back through the position of Figure 14 to that of Figure 13. At this point another clamping operation is carried out by points A and C and further upward movement at least of that portion of the motor adjacent the support is arrested. Since the force of gravity will be operative hereinafter to carry the structure downwardly it is not necessary that the free end of the spring have suflicient resilience left to continue its upward movement after the escapement has anchored the leftward end thus storing up power which augments the following downward movement, but such additional movement of the free end of the spring is most highly desirable. Thereupon gravity, whether or not augmented by the power stored in the spring by continued upward movement of its end, is operative 'torm lease the clamp AC and at this point to cause the motor to return to the position of Figure 15 through that of Figure 14. In both the upward and the downward cycles it will be noted that when the motor is in the position of Figure 14 points A, B and C do not engage the post and hence the entire structure is free to slip bodily downwardly along the post free of contact therewith for a small fraction of a second. These cycles are thereupon indefinitely continued until the motor has bodily fallen to the lower end of its support.

To secure satisfactory clamping action at the end of each phase of each cycle and also and more important to afford closely pre-controlled and regular oscillation certain principles must be followed, as outlined above. We have found that the separation of the two points on the same side of the post must be considerable. A practicable rule is that the diameter or width of a supporting post should be at least twice the separation of the two escapement points which are on the side of a post adjacent the body of the motor. That is, the distance between the escapement points on the one side of a post should be no less than one half of the distance representing the length of a horizontal line between a vertical line connecting them and the third point on the other side of the post when the device is disposed in the central or free neutral position. This clamping action of the escapement becomes important in connection with the minimum rather than the maximum weight. It must be suficient so that witha given minimum weight there is no slippage as distinct from the regular, pre-controlled and wanted bodily descent in each phase of each cycle in the position of Figure 14. When we are designing a device in which we desire maximum speed of vibration or frequency the spring which we choose must be completely without slippage before any load is applied. It will be readily realized that this condition or in fact any satisfactory operation cannot be reached with a device in which a leaf spring no matter what its thickness is mounted on a support by means of a central opening. Such mounting shows no escapement action whatsoever. It oscillates during short periods, but irregularly, and slides, slips and wobbles. No control is effective, we have found, unless the above factors are carefully included.

It will be understood that the further the escapement points on the same side of the support are separated in a vertical plane, their distance from that support in a horizontal plane being the same, the less the amplitude of vibration of the free end of the cantilever spring, and that on the other hand with increase of effective separation from a support in a horizontal plane, the vertical separation being the same, the great er the amplitude. Also, when the escapement consistsof a construction having four points of contact, arranged in pairs, the members of each pair being disposed in a horizontal plane, separation of those planes results in less amplitude while increase of the separation of the points of a pair within its horizontal plane results in increased amplitude.

In considering forms of our invention in which a lower clamping point is relatively far removed from an upper point, as in Figures 3, 7 and 11, it should be noted that we sacrifice some holding or clamping force, according to the ordinary laws of leverage, but unless the weight of the load is unusually light this loss is not 'of' importance, provided the above qualifications are :The foregoing arrangement of opening I40 and the :forward or escapement endof'the helical spring will be clearly seen from Figure 22. Provision of the relatively large opening MI and I42 above and below the leading coil I46 of the helix and the close restriction of the. opening at the sides I43 and I44 is to make the escapement action possible. As the spring oscillates it is necessary to supply space for an up-and-down movement above and below the leading end of the spring but to prevent side sway by close restriction. Limitation of this movement must be by engagement between the elements of the escapement and the support, according to principles previously described.

As also will be clearly noted from Figure 22 it is desirable that the extreme forward and front contacting loop I45 of the escapement be initially placed in a plane which intersects the longitudinal axis of the helix and is also horizontal.

As will be most clearly seen from Figures 12, 16 and 17 of this specification this escapement provides a three point contact between the motor and the support. The outer portion I48 (leftward as seen in Figure 16 and rightward as seen inFigure 17) of hook I45 provides contact on the side of support I I I relatively distant from the bird. Points I49 and I50, upon the hook and first coil respectively, form two points of contact upon the other or near side. which only two are operative at one time, one on the left side of the post and one of the two on the right side contact are very important in the operation. of the escapement as has been which rotation is obtained we shall present the physical principles underlying the foregoing.

- The direction and rate of bodily rotation of the device are determined by (1) the angle between the portion of the escapement nearer the motor and the adjacent coil of the spring thereof, hereinafter called the escapement angle, (2) the relation between the damped and un-damped portionsof the coils, and (3) the spacial relation between the side of which the coils are damped (or undamped) and the direction of opening of said escapement angle, all of which will be clear from a consideration of Figures 18, 19, 23, 24, 25 and 26 and the following portion of this specification. The second and third factors are more important. Rate of rotation reflects the number of times the motor and its load encircles its support in a given distance.

. To secure desired rotational characteristics, therefore, we change this escapement angle and also damp a portion or all of the coils on one side of the spring motor and leave the coils on the other sidefree to vibrate. Thus as will be seen in the figures ordinarily our spring motor takes a slightly arcuate form, the damped coils representing a shorter arc and the undamped coils a longer arc, indicated in Figures 18 and 19 as I53 and I54 respectively. An exception is described in connection with Figure 27.

' The first factor is of least relative importance.

These three points, of

The spring motor tends to rotate bodily into or toward this angle, thus placing this angle 1 on the trailing side. More important, however, is the positioning and extent of the damping of the coils. The tendency of rotation is away from the damped portion of the coils, the number of damped coils determining the rate of rotation. The increase of the rate of rotation of the motor as it descends, aside from increasing the escapement angle, depends solely upon the number of individual coils which are damped. So long as one coil is moved away from its adjacent coil far enough so that there is no damping no rotational effect is felt from that one coil. Then if one wishes to increase the rate of rotation he merely damps additional coils. The extent of damping between the coils is immaterial so long as the freedom to vibrate between 'adja cent coils is prevented.

The motors of Figures 23 and 24 are presented to illustrate this feature of our invention and for comparison with the motor of Figure 18.

Motor I61 of Figure 23 consists of a series of coils I62 which are damped on their short are I63, as defined above, and free for unlimited vibration on the long are I64. Forward 0011 IE5 is extended to form escapement I66 having opening I6! and embracing solid post III. Angle I58 between the escapement and the first coil will be noted as relatively large. Although this angle tends to cause rotation counterclockwise as in Figure 18 this effect is overbalanced by the damping of the coils upon that side. Since the relation between the undamped and damped portions of the coil is more powerful than the size or position of the escapement angle the rotation in this case is clockwise, as indicated by the arrow. Motor I6I may be supported and mounted as previously described. It should be remembered that some damping is always necessary to counterbalance the normal tendency of a helix composed of completely undamped coils to rotate bodily into the'escapement angle.

Figure 24 shows a motor as commonly built in accordance with this invention with certain of the coils damped and others free. Ordinarily it is not necessary to carry the damping throughout the entire spring. Motor I'II includes three series of coils of which series I12, most removed from the escapement, is clamped upon one side, central series I I3 with undamped coils and forward series I14 also damped. Escapement I15 embraces a post III and supplies an escapement angle I'IB. In this instance rotation is counterclockwise as indicated by the arrow in the direction or the arrow and away from the opening I".

' Figure 25, which is convenient for comparison with Figure 26, shows in fragmentary form a motor I88 including coils I8I terminating-in an escapementloop I82 having a hook I 83 and e's' capement angle I84 adjacent an outer loop I85.

It is by increasing or diminishing this angle that one important factor of the tendency to rotate may be controlled, although as previously stated mainder of the coils I93,'of which'only two are shown, are free. Escapement I94is as previously described except that escapement angle I95'5is 17 very slight. The slight tendency of angle I 95" to cause rotation in a counterclockwise direction is overcome by the tendency of damped coils I92 to cause clockwise rotation. This combination of forces results in perpendicular descent.

Figure 27 shows a convenient form of that embodiment of our invention in which the motor and its load descends perpendicularly, as in Figure 26 and production is even further simplified. In this case a motor 21! is not clamped by contact of its coils but a similar effect is obtained. A11 coils 2l2 are free to vibrate, except those anchored at the end of the motor relatively distant from the escapement 2 I4 and the one nearest the escapement. The wire of the most distant coil 215 is cut off sharply at 2|6 at a right angle to its longitudinal axis and near the middle of the coil. It is anchored within a ball 2|! as previously described by a speed nut 2| 8 and screw 2I9. As this screw is tightened the cutoff coil 2I5 causes the entire motor to be drawn slightly to the right and to form a closer contact with the right end 220 of opening 22I than with the left end. This pressure as at point 22l overcomes the tendency of escapement angle 222 between the escapement and first coil 223 to cause the device to rotate in a counterclockwise direction. The two forces being equal the device descends without rotation.

When use is made of a metallic or other strong container for the motor, in place of a light ball as in the structure we use as illustrative, we have found it convenient in production to damp the coils by a method which is not illustrated but can readily be understood by reference to Figure 27. When ball 2!? is made of material of sufficient strength helix 2 is placed therein with the cut-off coil 2|5 well spaced from the container and screw 219 tightened. This action draws the spring, longitudinally considered, into the form of an arc and is a convenient method of forming a structure such as that shown for example in Figure 23, but with the curvature on the opposite side of the helix.

In all forms of the invention the support or post should be formed of relatively hard metal so that its surface is not pitted by the escapement. Such lack of smoothness upon the surface interferes with smooth operation and accurate timing. Another precaution to be observed in such embodiment of our invention as that of the Woodpecker toy just described is to make sure that no part other than the contact points of the escapement engages the support and interferes with the smooth operation of the escapement.' For example if the beak of the Woodpecker engages the post slippage results because the beak then usurps the action of the upper right contact point but so far separated vertically from the plane of the opposite or leftward point that clamping action is destroyed and the entire device slips and falls.

In order to secure the full results of our invention it is desirable carefully to determine and apply certain critical factors to a helical spring, as well as to its escapement, as previously explained in connection with a leaf spring. These factors may be determined within wide latitudes.

It is first necessary to calculate the spring rate, which is the number of pounds required for each inch of deflection, as follows:

wherein:

=rate. P=1oad in pounds. F=defiection in inches.

8PD N W wherein (with the above value):

F=defiection in inches.

=load in pounds (1.00).

-D=mean diameter of spring, 1. e., outside diameter minus wire size (.625").

N=number of active coils (14).

G=modulus of the material in torsion, i. e. steel,

d=wire diameter in inches (.120").

When the above stated factors are substituted:

Thus with an assumed weight of unity the defiection in inches is .011.

With this value established and by the use of the first formula cited above we secure by the use of the following formula a spring rate as follows in pounds per inch of deflection:

P 1.00 R 91 pounds per mch Thus having learned that the spring rate is ninety-one pounds per inch and by this insertion of the weight of the spring actually used in one example only of our invention by the application of Ricardos formula the following results are secured:

n=531R/ W wherein:

n=complete number of free vibrations per minute of the spring as vibrating in itself.

R=rate of spring (91 pounds per inch of defiection).

W=weight of active mass in the spring (.096 1b.).

d=wire diameter (.120").

D=mean diameter (.625").

N=number of active coils (14).

By the application of the above formula with a substitution of known values it has been determined that the spring in question has frequency 'of 16,344 cycles per minute or 2722 per second as follows:

From the previous portion of this specification it is evidenced that for various applications different inherent vibrational frequencies predetermined are desirable. By varying the R and W values in Ricardos formula any desired result can be readily obtained.

We are aware that it has been proposed to use a. leaf spring for purposes which have a slight superficial resemblance to ours. For ex-:

ample a toy Woodpecker has been mounted upon a post by means of a leaf spring and descends in a series of jerky movements]? The proposer goes on to say There willbe zatendency of .the bird to wobble sidewise. Such jerking and wobbling are very different from the-pre-controlled and regular oscillations and rotation made posible by the'present invention.

Although many different applications "making useof aflatspring-haveproved the'effectiveness of our springmotors'made upon that basis, for many purposes, particularly when a considerable load is to be carriedgwe have found the relatively greater efficiency per unit of metal of a helical spring very helpful.

The advantages of our invention willhave been apparent from the foregoing specification and attached drawings, and reflected in the subjoined claims. They include the provision of method and meanswherebythe "force of gravity and resilience of a springzareiutilized-stoccarry=a load downwardly, and ifl'desiredirotationally, in a. series '7 of.;fully predetermined:-and::pre-timedin termittent steps. L'Iheytinciutle theaproizi'siomof an improved spring-.poweremmotorzembodyingor carrying an escapee lent.

We claim:

1. In a device :of the -:character :described, -a generally vertical support, -,a.canti1ever-.spring of which one end is 'free and the other end embodies .an escapement, said escapement consisting of formations spaced and/separate.from each other for lmounting .said :spring .upon said support for bodily descent therealongin regular .in-

termittentmovementsand ,withlits free end extending outwardly .from said ,support and -free of contact therewith, two of. said formations being engageable with=onesideof said supportand another formation being engageable with a side of said support opposite that .engagedby-said two formations, the distance between said two formations upon -.the.-samerside ofssaid supportbeing at least onehalfof the width-,of that ,portionof said supportdisposed between :said two formations .and said-other mentioned formation and said support and .said .esoapement during all phases of each cycle of movement .and1rest1being entirely free from engagement with each other except at the points oi'conta'ct between said formations and said support.

2. In a device according to claim 1, the end of sai'd'cantilever'spring which embodies said escapement-being formed-with an opening for said support and then being bent'first at substantially a right angle to the. main body of said spring and thence"backtoward'saidsupport and with its end engageable with said support at a point spaced from the main body of said spring, sides of said openings and saidend therebyacting both as an escapement and as :a mount :rcr ssaid =.spring:ifor intermittent bodilyidescent therealong,irr.a:series of regular intermittentrmcvements,: said end and the side of said openingreiatively: adjacentthereto being en ageable with saidzsuppo-rt .uponthe same side thereof.

3. A'device-according to claim '1 wherein "said escapement encircles saidsupport-andone of said two formations engageable ,with the same side of said support at saiddistanee is ;dispcsed-above and the other isdisposed :below the plane ofsuch encirclernent.

i. In a device (of Zthe character described, :a generally vertical support, :a gravity operated spring motor including an escapement, said spring motor b'eing fol'me'd "of a leaf spring, i a q i e;

20 spring lbeing disposed .with iits flat sides in "generally' horizontal planes, an end portion 'o'f :said spring Ibeing bent at substantially a :right angle to the: main body of the spring to iorma first extension andcthen again'bent 'back upon itself at right: angles'tosai'd first extension in a direction parallel to the. main body -:of r'saidspring 'to' form a. second extension, said; maimbodyoandisairl second extension: eachcbeing' formed with an. opening forithe receptionof said support,tsaidsopenings being aligned, the peripheriespf said: operiings in' said :main portion :and said second extension thereby :both1acting as :an escapement and :also as :a :mount for said spring :for tbodily descent therealong in .a series "of regular iintermittent mcvementsland'withzthe flit-3856116. of 'therspring extending raway from :;the said rsupport.

iIn zacdeviere :of 'a character described, aagenerally vertical support, :a gravity :operated: spring motonincludingaan escapement,ssaidspring motor being formed aU f .a leaf :spring, :said leaf spring being disposed with its flatrsidesiinrgeneraliyshorizontal gplanes and cone :free end :being fdisposed relatively distantly from said support, ithe a other end .po'rtionnof said-springnbeinghentzat:substantially a right angleof :the m-ain body of.:the:sprmg to 'form'a first extension and then sagainzbent back upon itself in: the 1 direction.ofrssaidsfreewentl of said spring to formza second extension, 'said mainrbodyiand saidssecondeextensionseach :b'eing formed'with an opening .for' thesreceptioncofasaid support, said openings being aligned, athezperiphcries of :said openings 2 in said main '1 portion zand said "second extension l thereof acting both :as sescapement and: also-asia mount for: such-'springifor bodily descent .along :said support in a :eseiies .of regular intermittent movements.

6. In a timer, a: .general ly uprightrsupport, and agravity-.operated.- spring timingsniotorzincluding anescapenrent said:motor:includingra cantilever leaf spring free to vibrateiatuonexendzand the other i end of said -.spring including :said escapement, said .escapement having format-ions :by which said spring may :be mounted upon said support near the top-thereof for descent therealong in. a series of :pre-timedand regularf intermittent movements with theireecend of said spring extending-away.irom saidsupport, two of said format-ionssengaging'onezside ofsaidsupport at vertically spaced-pointsandat least- .one engaging .an- Opposite .side, .calibrations upon said leaf springatdifieren-tdistances: from, its pointof:attachment .to said support, .2. weight, :and :means forfixing .said weight --to said spring :in accordance with saidcalibrations.

.7. In atimer a gravity-operatedspringtiming motor,. asupport therefor, a mount -.for-;said, support, said mount including means :formaintaining said support. in .a vertical ,position and ate plurality .of angles to the vertical, .said motor comprising a cantilever spring .and an escapement, said escapement including a plurality .of formations by which said cantilever spring may bemounted upon said support'near the .top thereof for intermittent movement *downwardlytherealong, two of said formations "being "engageable with saidsupport upon one side thereof at spaced points and anotherbeing-engageablewith the side of said support opposite to that-which is engaged by said two formations and the 'free end of said spring extending. away from said'supportmalibrations upon said support, -a-stop"movable along said support for limiting the downward travel of said motor, means for fixing said stop to said support in accordance with said calibrations.

calibrations upon said leaf spring at different distances from its point of attachment to said support, a weight, and means for fixing said weight to said spring in accordance with said calibrations.

8. In a device of the character described, a generally vertical support, a gravity-operated spring motor including an escapement, said spring motor being formed of a leaf spring one end of which is free and the other end of which includes escapement means for attaching said motor to its support at substantially a right angle thereto and for intermittent bodily downward movement therealong, said attaching means including two formations engageable with one side 15 of said support at a distance between the lines of engagement of said two formations with said one side of said support no less than one half of the width of said support in a direction along the long axis of said spring and another formation 20 engageable with said support upon the side thereof opposite that engaged by said two formations, said support and said spring motor during all portions of each cycle of movement and rest being entirely free from engagement with each other except at the points of contact between said formations and said support.

ELSIE BREDIMUS.

WARREN DUNHAM FOSTER.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 350,766 Pattyson Oct. 12, 1886 1,050,234 Rowe Jan. 14, 1913 1,649,645 Allen Nov. 15, 1927 1,677,463 Snedeker July 17, 1928 2,149,677 Hojnowski Mar. 7, 1939 

